Open beta · Free for solo devs

Design backends
like a senior architect.
Ship with confidence.

Visual canvas, constraint-aware AI, real-time multi-cloud pricing, and architecture health scoring — all in one collaborative workspace for backend teams.

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No credit card
3 free diagrams
SSO with GitHub or Google
Ride-sharing Backend · v4
⬡ 74$847/mo
CLIENTmobile / webAPI GATEWAYrate limit · authAUTH SERVICEJWT · OAuthUSER SERVICEprofiles · prefsORDER SERVICErides · trackingPOSTGRESQLRDS · t3.largeREDIS CACHEElastiCacheSQS QUEUEasync jobs!⚠ No DLQ configured
AI Assistantclaude
Design ride-sharing backend for 10k users
BackArch AI
Foundation laid. Your SQS has no DLQ — at 10k req/s you'll lose ~0.1% of messages.
Suggestion
Add circuit breaker between Order → PostgreSQL. Apply →
Monthly Cost
☁ AWS$847
☁ GCP$743
☁ Azure$921
Visual Canvas

The canvas backend
teams have been missing.

Drag, connect, and reason about your system visually. Every component — API gateways to vector DBs — ships pre-wired with correct connection semantics.

40+ componentsTyped connectionsAuto-save + versioning
CLIENTAPI GATEWAYKong · rate limitAuthUsersOrdersPGprimaryComponents+ Lambda+ Kafka
Constraint-First AI

AI that actually understands
your constraints.

Set your budget, cloud preference, traffic, and compliance posture. The AI never suggests $2k/mo Kafka when you're on a $500 budget.

Claude Sonnet-poweredDiagram-aware contextOne-click mutations
BackArch AIclaude-sonnet
☁ AWS💰 $500–2k/mo⚡ 1k req/s👥 3 eng
Add async queue between orders and fulfillment
BackArch AI
Given your $500–2k budget, I'd recommend SQS FIFO(~$24/mo) over Kafka (~$350/mo). I'll add a DLQ and Lambda consumer to keep you serverless.
The Modeling Suite

Beyond boxes and arrows.

Three first-class modeling surfaces for the parts of your system the topology can't capture — behavior, conversations, and data — all stitched to your canvas.

01State Machine Designer

Model behavior, not just boxes.

Draw the states. Simulate the flow. Export to XState in one click.

Every backend has hidden behavior — workflows, lifecycles, status transitions — that boxes-and-arrows diagrams completely miss. The State Machine Designer makes those flows visible, testable, and exportable.

  • Initial / final / choice / fork / join states out of the box
  • Typed transitions with events, guards, and actions
  • Built-in simulator — step through your machine event by event
  • Export to Mermaid, PlantUML, or XState JSON
Open editor →
PENDINGentry / logapproveACTIVEdo / processretryreject / logSIM · step 3 of 5
02Sequence Diagram Editor

Make every conversation legible.

Lifelines, messages, fragments. UML you'll actually want to maintain.

The Sequence Diagram Editor turns service-to-service conversations into a first-class artifact. Capture the exact order of calls, returns, async fan-outs, and error paths — and keep them in sync with your architecture.

  • Actors, services, databases, queues, and external lifelines
  • Sync, async, return, self-call, and create/destroy messages
  • Fragments for alt, loop, opt, and par blocks
  • Export to Mermaid sequenceDiagram or PlantUML
Open editor →
ClientOrderSvcPaymentDBcreateOrder(items)charge(amount)paymentIdnotify{ orderId }alt
03Data Model Designer

Design schema. Ship migrations.

ERDs that compile to PostgreSQL, MySQL, SQLite, Prisma, or TypeScript.

The Data Model Designer is the database canvas your team has been hand-rolling in dbdiagram.io and then losing in Notion. Entities, fields, typed relationships — all version-controlled alongside your architecture.

  • Tables, views, enums, interfaces, and abstract classes
  • Typed fields with constraints, defaults, and indexes
  • 1:1, 1:N, N:M, and inheritance relationships
  • Export to PostgreSQL · MySQL · SQLite · Prisma · TypeScript · Python · Java
Open editor →
User🔑iduuid✉emailvarchar•namevarchar•createdAttimestamp1NOrder🔑iduuid↳userIdfk•totaldecimal•statusenum→ schema.prismaDB · CODE
Architecture Health

Your architecture score,
live as you build.

Every change updates a real-time 0–100 score across resilience, security, scalability, and cost efficiency.

0
/ 100
SPOF detection
Flags services with no redundancy
Missing circuit breakers
Detects unprotected service calls
No DLQ on queues
Your SQS has no dead-letter queue
Observability coverage
Checks for metrics, logs, traces
Auth layer present
Verifies auth on public endpoints
Budget compliance
Flags components over your limit
Design Patterns

Battle-tested patterns,
built right in.

Apply proven patterns in one click. The canvas annotates them visually and explains tradeoffs inline.

40+
Patterns
5
Categories
1-click
Apply to canvas
AI
Tradeoff analysis
⚡
Resilience
Circuit Breaker
Stop cascade failures by halting calls to degraded services automatically.
Medium
🔀
Scalability
CQRS
Separate read and write models for independent, elastic scaling.
Hard
📬
DataDistributed
Saga Pattern
Coordinate distributed transactions across microservices without 2PC locks.
Hard
🛡
Networking
API Gateway
Single entry point for all client-to-service communication with auth and rate limiting.
Easy
📊
StateAudit
Event Sourcing
Persist state as an immutable event log for full auditability and time-travel.
Hard
🔄
Resilience
Retry + Backoff
Exponential backoff with jitter for graceful transient-fault recovery.
Easy
Browse all 40+ patterns  →
Live Multi-Cloud Pricing

Know the real cost
before you provision anything.

Every component you place gets a live price tag sourced from AWS, GCP, and Azure APIs — refreshed weekly. Zero spreadsheets.

1,000+
Pricing records
3
Cloud providers
Weekly
Price refresh
50+
Service types
AWS
Amazon AWS
$847/mo
↑ $104 vs GCP
EC2 t3.large$168
RDS PostgreSQL$384
ElastiCache$165
SQS + Lambda$130
CHEAPEST
GCP
Google Cloud
$743/mo
↓ saves $1,248/yr
Compute n2$142
Cloud SQL$348
Memorystore$143
Pub/Sub + Run$110
AZ
Microsoft Azure
$921/mo
↑ $178 vs GCP
VM D2s v3$191
Azure SQL$412
Azure Cache$178
Service Bus$140
Monthly spend — ride-sharing backend
AWS
$847
$847
GCP
$743
$743
Azure
$921
$921
AI model pricing
claude-sonnet-4-6Recommended$3 / $15 MTok
claude-haiku-4-5Fastest$0.80 / $4 MTok
gpt-4oOpenAI$2.50 / $10 MTok
gemini-2.0-flashGoogle$0.10 / $0.40 MTok
✦
BackArch AI: Switching this stack from AWS to GCP saves $104/mo ($1,248/yr) with near-zero migration cost — same managed services, different billing. Apply to canvas to see the updated diagram.
See subscription plans →Explore pricing explorer
Coming Soonon the roadmap
Real-time Collaboration

Your whole team,
on the same canvas.

See teammates' cursors, selections, and edits live. Built on Y.js CRDTs — no merge conflicts, no lock contention. Just flow.

Y.js CRDT engineLive presence cursorsMultiplayer awareness
AKSRJM3 collaborators · liveAPI GatewayKongUser ServicePostgreSQLAlexSamJordanRedis Cache
Pricing

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Free forever · 3 diagrams · SSO with GitHub or Google